(function (doc: Document, win: Window) {
  const docEl: HTMLElement = doc.documentElement;
  const resizeEvt: string = 'orientationchange' in win ? 'orientationchange' : 'resize';

  const recalc = () => {
      const clientWidth: number = docEl.clientWidth; // 获取设备尺寸
      if (!clientWidth) return;

      if (clientWidth >= 750) { // 设计稿宽度
          docEl.style.fontSize = '100px';
      } else {
          docEl.style.fontSize = `${100 * (clientWidth / 750)}px`;
      }
  };

  if (!doc.addEventListener) return;
  win.addEventListener(resizeEvt, recalc, false); // 绑定事件
  doc.addEventListener('DOMContentLoaded', recalc, false);

})(document, window);
